code: def configure_settings(settings):
      """Provide optimizations, error checking, and warnings for the given
      settings.
      Also, specify the log messages to be ignored.
      """
      if "PATH" not in settings or not os.path.isdir(settings["PATH"]):
          raise Exception(
              "You need to specify a path containing the content"
              " (see pelican --help for more information)"
          )
  
      # specify the log messages to be ignored
      log_filter = settings.get(
          "LOG_FILTER", DEFAULT_CONFIG["LOG_FILTER"]
      )
      LimitFilter._ignore.update(set(log_filter))
  
      # lookup the theme in "pelican/themes" if the given one doesn't exist
      if not os.path.isdir(settings["THEME"]):
          theme_path = os.path.join(
              os.path.dirname(os.path.abspath(__file__)),
              "themes",
              settings["THEME"],
          )
          if os.path.exists(theme_path):
              settings["THEME"] = theme_path
          else:
              raise Exception(
                  "Could not find the theme %s" % settings["THEME"]
              )
  
      # standardize strings to lowercase strings
      for key in ["DEFAULT_LANG"]:
          if key in settings:
              settings[key] = settings[key].lower()
  
      # set defaults for Jinja environment
      settings = get_jinja_environment(settings)
  
      # standardize strings to lists
      for key in ["LOCALE"]:
          if key in settings and isinstance(settings[key], str):
              settings[key] = [settings[key]]
  
      # check settings that must be a particular type
      for key, types in [
          ("OUTPUT_SOURCES_EXTENSION", str),
          ("FILENAME_METADATA", str),
      ]:
          if key in settings and not isinstance(settings[key], types):
              value = settings.pop(key)
              logger.warn(
                  "Detected misconfigured %s (%s), "
                  "falling back to the default (%s)",
                  key,
                  value,
                  DEFAULT_CONFIG[key],
              )
  
      # try to set the different locales, fallback on the default.
      locales = settings.get("LOCALE", DEFAULT_CONFIG["LOCALE"])
  
      for locale_ in locales:
          try:
              locale.setlocale(locale.LC_ALL, str(locale_))
              break  # break if it is successful
          except locale.Error:
              pass
      else:
          logger.warning(
              "Locale could not be set. Check the LOCALE setting, ensuring it "
              "is valid and available on your system."
          )
  
      if "SITEURL" in settings:
          # If SITEURL has a trailing slash, remove it and provide a warning
          siteurl = settings["SITEURL"]
          if siteurl.endswith("/"):
              settings["SITEURL"] = siteurl[:-1]
              logger.warning(
                  "Removed extraneous trailing slash from SITEURL."
              )
          # If SITEURL is defined but FEED_DOMAIN isn't,
          # set FEED_DOMAIN to SITEURL
          if "FEED_DOMAIN" not in settings:
              settings["FEED_DOMAIN"] = settings["SITEURL"]
  
      # check content caching layer and warn of incompatibilities
      if (
          settings.get("CACHE_CONTENT", False)
          and settings.get("CONTENT_CACHING_LAYER", "") == "generator"
          and not settings.get("WITH_FUTURE_DATES", True)
      ):
          logger.warning(
              "WITH_FUTURE_DATES conflicts with CONTENT_CACHING_LAYER "
              "set to 'generator', use 'reader' layer instead"
          )
  
      # Warn if feeds are generated with both SITEURL & FEED_DOMAIN undefined
      feed_keys = [
          "FEED_ATOM",
          "FEED_RSS",
          "FEED_ALL_ATOM",
          "FEED_ALL_RSS",
          "CATEGORY_FEED_ATOM",
          "CATEGORY_FEED_RSS",
          "AUTHOR_FEED_ATOM",
          "AUTHOR_FEED_RSS",
          "TAG_FEED_ATOM",
          "TAG_FEED_RSS",
          "TRANSLATION_FEED_ATOM",
          "TRANSLATION_FEED_RSS",
      ]
  
      if any(settings.get(k) for k in feed_keys):
          if not settings.get("SITEURL"):
              logger.warning(
                  "Feeds generated without SITEURL set properly may"
                  " not be valid"
              )
  
      if "TIMEZONE" not in settings:
          logger.warning(
              "No timezone information specified in the settings. Assuming"
              " your timezone is UTC for feed generation. Check "
              "https://docs.getpelican.com/en/latest/settings.html#TIMEZONE "
              "for more information"
          )
  
      # fix up pagination rules
      from pelican.paginator import PaginationRule
  
      pagination_rules = [
          PaginationRule(*r)
          for r in settings.get(
              "PAGINATION_PATTERNS",
              DEFAULT_CONFIG["PAGINATION_PATTERNS"],
          )
      ]
      settings["PAGINATION_PATTERNS"] = sorted(
          pagination_rules,
          key=lambda r: r[0],
      )
  
      # Save people from accidentally setting a string rather than a list
      path_keys = (
          "ARTICLE_EXCLUDES",
          "DEFAULT_METADATA",
          "DIRECT_TEMPLATES",
          "THEME_TEMPLATES_OVERRIDES",
          "FILES_TO_COPY",
          "IGNORE_FILES",
          "PAGINATED_DIRECT_TEMPLATES",
          "PLUGINS",
          "STATIC_EXCLUDES",
          "STATIC_PATHS",
          "THEME_STATIC_PATHS",
          "ARTICLE_PATHS",
          "PAGE_PATHS",
      )
      for PATH_KEY in filter(lambda k: k in settings, path_keys):
          if isinstance(settings[PATH_KEY], str):
              logger.warning(
                  "Detected misconfiguration with %s setting "
                  "(must be a list), falling back to the default",
                  PATH_KEY,
              )
              settings[PATH_KEY] = DEFAULT_CONFIG[PATH_KEY]
  
      # Add {PAGE,ARTICLE}_PATHS to {ARTICLE,PAGE}_EXCLUDES
      mutually_exclusive = ("ARTICLE", "PAGE")
      for type_1, type_2 in [
          mutually_exclusive,
          mutually_exclusive[::-1],
      ]:
          try:
              includes = settings[type_1 + "_PATHS"]
              excludes = settings[type_2 + "_EXCLUDES"]
              for path in includes:
                  if path not in excludes:
                      excludes.append(path)
          except KeyError:
              continue  # setting not specified, nothing to do
  
      return settings
  
file_path: pelican/pelican/settings.py
imports: import copy
  import importlib.util
  import inspect
  import locale
  import logging
  import os
  import re
  import sys
  from os.path import isabs
  from pathlib import Path
  from pelican.log import LimitFilter
label_desc: Use image node_id 8 for calling a global function with example usage: configure_settings(settings) and returns: settings